Efficacy and synergy of live-attenuated and inactivated influenza vaccines in young chickens
Birds were vaccinated at 1 day of age and challenged with heterologous virus (CK/NJ/02 (H7N2)) at 2 weeks post-vaccination. Following challenge, full tracheas were collected and washed with 2 ml of PBS and the replication level of challenge virus was determined by qRT-PCR. Virus titers are expressed as median egg infectious doses per ml of tracheal wash supernatant. (A) 3 days post-challenge. (B) 5 days post-challenge. Different letters inside the plot indicate statistical significance among groups (p<0.05).